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Unprecedented: Dormant black hole caught ‘waking up’ to devour a star

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Scientists reported Wednesday that they witnessed in unprecedented detail a star being ripped to shreds and devoured by a dormant supermassive black hole.

The celestial feeding frenzy — known as a tidal disruption event — was detected from the high-energy, X-ray echoes emitted as debris from the hapless star swirled in a vortex near the black hole’s centre.

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The findings were published in the prestigious science journal Nature.

“Never before have we been able to see strong gravity effects from a dormant black hole,” Erin Kara, a Hubble postdoctoral fellow at the University of Maryland, and lead author of the study, told AFP.

Black holes are regions in space-time where mass is collapsed into such a small area that gravity takes over completely, and nothing — not even light — can escape.

They cannot be seen, and are inferred from their influence on nearby objects.

Most of what astronomers know about so-called supermassive black holes — found at the centre of galaxies — comes from a relative handful that actively gather and consume matter.

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Roughly 90 percent are dormant, only awakening from time to time to gulp down anything that passes too close.

When that happens to a star, it disappears in a swirling flash of energy and light.

– Slumbering giant –

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“Most tidal disruptions don’t emit much in the high-energy X-ray band,” Kara explained.

Only three such episodes have ever been recorded, “and this is the first such event that has been caught at its peak”.

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The tell-tale signs from this particular slumbering giant, dubbed Swift J1644+57, were picked up by NASA’s Swift satellite, the researchers reported.

Three more satellites — one from the European Space Agency, another from Japan, and a third from NASA — tuned in to the event, yielding a treasure-trove of “excellent data”.

The fact that X-rays could be detected at all stems from the amplifying effect of the so-called accretion disk — the doughnut-like swirl of matter falling into the black hole.

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Scientists had previously thought X-rays generated in the death throes of a disintegrating star came from huge beams of particles already ejected by the black hole.

The new observations tell another story: “Actually, we can see this reverberation at work very close to the central black hole,” Kara said.

Black holes that are dormant today played a key role in the evolution of galaxies, so seeing one in action may provide clues about the formation of the Universe, said co-author Chris Reynolds, a professor at the University of Maryland.

“If we only look at active black holes, we might be getting a strongly biased sample,” he said in a statement.

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One of the crucial unanswered questions about black holes, for example, is how fast they rotate, or spin. Knowing this would yield valuable clues on how they form and mature.

One theory suggests that black holes become dormant after they reach “maximal spin”, in which case they should all be spinning at the same rate.

Another says black holes only grow by merging with each other, in which case spin rates would be more variable.


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‘Hell no’: Texans join forces to stop Trump from stealing their land

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President Donald Trump's pledge to build a wall at the southern border with Mexico has been a huge winner with his base. But there is one group of people who are not happy: the Texans who actually live in the region where the wall would be built.

According to the Washington Post, many people in the region have no intention of letting the federal government seize their land to construct the wall, like Afghanistan war veteran Salvador Castillo of Brownsville, who received a letter from officials demanding unlimited access to and use of his land, which gradually escalated into a lawsuit.

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Pearl Harbor veteran to be interred on sunken ship

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It was an attack that shaped history, leaving more than 2,400 Americans dead and forcing the United States to enter a war it had been reluctant to join.

On Saturday, the 78th anniversary of the 1941 sneak attack by Japan on Pearl Harbor, the remains of one of the survivors of the assault will be interred on his sunken ship, the USS Arizona.

Lauren Bruner, who was among the last sailors rescued from the Arizona as it exploded into flames and sank, died in September at age 98.

He had expressed in years past his wish to be buried alongside fellow sailors who died on that fateful day.

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Suspect swallows poison after verdict in French murder case

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The suspect for the rape and murder of a young woman in northern France almost two decades ago was under guard in hospital Saturday after he swallowed pesticide in an apparent suicide bid following his conviction.

Willy Bardon, on trial over the murder of Elodie Kulik in 2002 in a case that has attracted strong interest in France for years, ingested the substance at the courthouse in the northern city of Amiens late on Friday.

Bardon had been sentenced to 30 years jail for kidnapping and holding a person against their will followed by death. He was however acquitted of murder.

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